seem to be due to a gouty disposition or.tendency, and in many forms of hepatic derangement. This method of treatment was employed for many years by Dr. Todd, and I think before him by Mr. Ure, one of the surgeons of St. Mary's Hospital. Benzoic acid acts upon glycocine in the liver, to form hippuric acid, and it is probably to this chemical action that the benefit resulting from its use should be attributed. The reader will gain important information on this matter, as well as concerning the probable action of many chemical remedies in gout and allied affections, from Professor Latham's work "On the Formation of Uric Acid in Animals: its relation to Gout and Gravel." Cambridge: Deighton Bell. 1884.

I have seen instances of uric acid deposits occurring in adults, over which ordinary remedies appeared to exert little influence. The urine of a patient suffering from emphysema of the lungs always contained a large quantity; and it appeared while she was taking considerable doses of alkalies, and also when she was put upon mineral acids.

The occasional deposition of uric acid crystals from the urine requires no medical treatment, or at most a dose of bicarbonate of potash after meals or the last thing at night. In some cases in which these deposits are frequent, and in people of a gouty tendency, small doses of hydrochloric acid with pepsin before meals, and twenty grains of bicarbonate of potash in half a tumbler of water after meals, is a plan which answers admirably, and often cures the patient after other methods have completely failed.

Of all the remedies employed for carrying off uric acid from the system liquor potassæ is, in my opinion, the most efficacious. The objections sometimes urged against the use of liquor potassæ are not established by the facts of experience, unless it is persisted in for too long a time, or given in cases when its use is contraindicated. Where an unusual proportion of uric acid is formed, as much as a drachm of liquor potassæ has been taken daily for many months without any ill effects, though, as a general rule, I should not advise the drug to be given in more than half the proportion, or for more than a fortnight at a time

without an interval during which it is withheld altogether. A gentleman of 60, who had been passing small uric acid concretions from the kidney, sometimes to the number of 100 or more in a single week, was ordered to take liquor potassæ. After a time, the stones ceased to appear. But, without the knowledge of his medical adviser, this gentleman continued to take liquor potassæ daily for upwards of twelve months, in quantities of from twenty to sixty drops daily. The acid reaction of the urine continued during the whole time. Such a case conclusively proves what a large amount of alkali may be taken for a considerable time without detriment-indeed, with great advantage to the patient. This patient was muscularly weak, but he found that he felt better and stronger when taking liquor potassæ than he had done for many years before, while his lumbar pain ceased to trouble him, and the calculi only made their appearance very occasionally. However, as I have already remarked, it is desirable not to give liquor potassæ for longer than a fortnight at a time. After an interval of a week or two, the remedy may be resumed for a like period. In prescribing acids and alkalies, and, indeed, all other remedies, the practitioner should feel sure that the patient understands how long he is to continue the drug. It is very important we should know how far the frequent administration of potent remedies may be pushed with advantage, and without being detrimental to the patient. Unfortunately information of this kind is for the most part in the heads of practitioners, and so far little exact knowledge on the matter has found its way into treatises on medicine and therapeutics. are instructed as to the doses in which a drug should be prescribed, but it is seldom we meet with exact directions which we can apply to the management of a given case. Much is still left to the experience, judgment and medical sagacity of the individual practitioner. Unfortunately, it is almost impossible to record in a form that would be practically helpful the results of individual observation and experience by the bedside, and, indeed, when attempts are made to do this, except in the most broad and general way, it is not possible to avoid prolixity and detail which would be tedious to read, and would practically be

We

of little assistance even to the few who took the trouble to wade through what was written. This is no doubt why, as students and practitioners often complain, many practical questions of the simplest and broadest character remain almost unanswered, not only in our text-books, but in our books of reference, encyclopædias, and dictionaries. Nay, still there remains much uncertainty concerning broad principles upon which the treatment of well-known and common forms of disease should be conducted. We still have to appeal to the judgment of those who have had greater experience than ourselves, or to trust to our own. The actual practice of medicine, the treatment of actual cases of illness, changes so much from decade to decade, that it is not to be wondered at that our so-called "principles " are often called in question, and are regarded as prejudices and fads of advisers full of confidence in themselves, more positive than thoughtful-" principles" founded upon egotistic imagination, upon dictum, upon fashion, rather than upon fact and observation. Nevertheless, there are principles by which we may be guided, and which rest upon a very firm and solid basis of fact.

XANTHINE.

Uric or Xanthic Oxide (C10H,N,O) is a substance closely resembling uric acid in many of its characters. It is very rarely met with in urine. It was described first by Marcet, and has since been detected in the blood, and also in the spleen, muscles, liver and brain. It is rarely met with in the crystalline form, but Bence Jones reports the case of a boy, aged 91⁄2 years, suffering from a feverish attack, in whose urine xanthine crystallized in lozenge-shaped crystals, which were first mistaken for uric acid. ("Journal of the Chemical Society," 1862.) The crystals were dissolved when the urine was boiled, and were found to be soluble in water, nitric and hydrochloric acids, and in all alkalies. Douglas Maclagan also reports a case in which xanthine occurred in a urinary deposit. The synthesis of xanthine has been effected by Gautier, from hydrocyanic acid, and no doubt ere long uric acid will be obtained from xanthine. Xanthine is probably a common constituent of urine, but exists in very small

quantity. According to Dr. John Davy, it is the constituent of the urine of spiders and scorpions. A rare form of calculus is entirely composed of it. Dr. G. Durr, after bathing in natural sulphuretted waters, found xanthine in his urine, and also in the urine of a patient who had had strong sulphur ointment rubbed into his skin, but not after taking milk of sulphur into his stomach.

DEPOSITS OF OXALATE OF LIME.

Oxalate of lime was first shown to be a common urinary deposit by Dr. Golding Bird. It is seldom deposited in quantity sufficient to be recognized by the naked eye, or to be tested chemically. Oxalate of lime crystallizes in well-defined octahedra-easily seen, if very minute, under a quarter of an inch object-glass.

There is still much difference of opinion among practitioners as to the clinical importance of oxalate of lime. There can be no doubt that, in many instances, the crystals form after the urine has left the bladder. The conclusions of Dr. Owen Rees, and the experiments of Dr. Aldridge, indicate that the oxalic acid is produced by decomposition of the urates after the urine has been secreted. Oxalate is often found in the urine of gouty cases, and it is certainly very commonly detected among urate deposits. Although there are many abnormal conditions of the system, in which both oxalates and urates are very common, both deposits may be present, and, indeed, very commonly are present in the urine of healthy persons. Hence, it is obvious that such deposits do not necessarily establish the existence of any particular diathesis. What is termed the "oxalic diathesis," seems to have derived its name from the fact that oxalate of lime is present in the urine; but this is not the most important part of the case, and the practitioner cannot make a greater mistake than to direct his attention to the urinary deposit alone, or to consider this as a special indication for treatment. In the same case, at one period we find uric acid and urates; after a time, these mixed with oxalates; and lastly, oxalate alone, and there will probably be found in connection with the symptoms, clinical facts of far greater consequence, especially as regards the ques

tion of treatment, than the presence of oxalate of lime in the patient's urine.

Wöhler and Frerichs injected uric acid into the blood of a dog, and found oxalate of lime in the urine. Oxalate of lime passes through the alimentary canal unchanged; but oxalic acid is, in part, excreted in the urine, while part is decomposed in the system. Buchheim and Piotrowsky have shown that small repeated doses of oxalic acid (fifteen grains every hour for six hours) are not poisonous. I should, however, strongly dissuade any one from repeating such an experiment. Not more than 12 per cent. of the oxalic acid taken by the mouth appears in the urine. I have detected oxalate of lime in the urine of several persons who have attempted to poison themselves with oxalic acid. In "100 Urinary Deposits," Pl. VII, Fig. 90, are so me very marked six-sided crystals of oxalate of lime, obtained from the urine of a patient who had taken a large quantity of oxalic acid. They were insoluble in water, and were not dissolved by potash or acetic acid. The refraction of the crystals corresponded with that of oxalate.

Oxalate of lime is, however, not always formed after the urine has been passed, indeed, it is often present while the urine remains in the bladder. Besides being found in octahedra in the urinary organs, or after the urine has left the bladder, oxalate of lime crystallizes in a different form altogether. It crystallizes in mucus in the form of spherules or "dumb-bells," and these, as I have shown, are often deposited in the tubes of the kidney during life. The crystal must, therefore, have been formed at the time of the separation of the urine from the blood, if, indeed, the salt did not exist in solution in the blood itself. The spherical and dumb-bell crystals, I have proved, often constitute the nucleus of uric acid and other calculi, and around it the other constituents are deposited in successive layers. It appears, then, that oxalate of lime may be excreted in the urine when oxalic acid or oxalates are taken in the food. It may be formed in the organism itself. It may be produced by the decomposition of uric acid and urates after the urine has left the bladder, and it may be deposited in the uriniferous tubes.